tps voltage problem????
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New User
Joined: Jul 2009
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tps voltage problem????
hi all..im new here so a big hello...now down to buisness...i have a 93 f 250 5.8...i got a tps code so i went to make sure it was adjusted properly or if it was bad..i have done this on both my mustangs and many other fords...im not new to tps adjustment...heres the problem..at idle position the sensor only read 0.12 volts and at full throttle it only reads 1.27 volts...i know it should be around 0.98 to 0.99 with the engine not running and at full open 4.50 to 5 volts...i tried taking it off the throttle body,sticking a volt meter to it and fully opening it and can only get 1.27 volts...when i probe the orange wire i get 5 volts steady...i know there is something wrong....any clues...my truck is also idleing rough and sputters at very little throttle but is find half throttle and up to full..and the idle is very low all of the sudden..starts great high idles like normal for a few then drops almost killing the engine...thanks for any help
Senior User
Joined: Mar 2009
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From: N.B., Canada
Well it certainly isn't working right. When you open it it should get close to 5V and closed it should read .5v-1v. Although it doesn't seem right that it works good at WOT it is definitely not working right and replacing it should fix the issue.
Senior User
Joined: Mar 2009
Posts: 253
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From: N.B., Canada
If your input voltage is right the output should be correct also unless of course the TPS is bad but you said you have tried 3 now. Are you probing the return wire and the ground wire, not the frame ground or battery?
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ive tried grounding at the plug,at a main ground junction,and at the battery and they all read the same..i just went and checked the tps on my mustang and it comes up perfect..theres something wrong with the voltage coming to the tps on this truck
Senior User
Joined: Mar 2009
Posts: 253
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From: N.B., Canada
Didn't you say that you get 5V on the power in? If so the only thing that could be wrong is the TPS... Try the one off that mustang.
It's always possible that the new ones are bad. Perhaps the TPS is right. That dieing idle could also be cause by a clogged IAC, either way cleaning it out won't hurt. Then it wont leave you stranded for another 50k.
It's always possible that the new ones are bad. Perhaps the TPS is right. That dieing idle could also be cause by a clogged IAC, either way cleaning it out won't hurt. Then it wont leave you stranded for another 50k.
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Fleet Mechanic
Joined: Nov 2022
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However you can test the resistance levels of the sensor.
Laughing Gas
Joined: Oct 2014
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From: Carnation, Wah
Try backprobing the TPS connector when it's hooked up to the truck- it's possible the 5v supply
in the PCM has gone soft, and can't hold 5v across the TPS... so it meters OK when the TPS is unplugged,
but when you plug it in it gets dragged down to 1.27v. Or there's a corroded connection at the PCM, or sum'fin...
t
in the PCM has gone soft, and can't hold 5v across the TPS... so it meters OK when the TPS is unplugged,
but when you plug it in it gets dragged down to 1.27v. Or there's a corroded connection at the PCM, or sum'fin...
t
Cross-Country
Joined: Nov 2024
Posts: 54
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they are a wear part, like spark plugs and glow plugs, and can develop dead spots in them. Best to replace, they aren’t that spendy.
Fleet Mechanic
Joined: Nov 2022
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It's a $70-$100 sensor, I'd say that's worth testing.